Wet wells are used to transfer wastewater, especially sewage liquids. Although gravity is typically employed for this transfer, wet wells are used in the occasions where a pump-assisted pressure lift is required. Wet wells collect wastewater through an influent pipe and contain the wastewater until a sufficient amount for transfer is gathered. A pump, typically a submersible pump, is mounted low in the wet well. When a level-sensing means actuates the pump, the accumulated wastewater is discharged, lifting the wastewater through a pressurized piping arrangement inside the wet well to an effluent pipe, through which the wastewater exits the wet well and continues on its way to a treatment facility.
The wet well almost always has a significant headspace present above the liquids, and the composition of the gases present in the wet well will require the wet well to be considered as a hazardous location, requiring equipment that is rated explosion-proof. Specific equipment requiring this rating includes at least the pump itself (including its associated motor), the level-sensing system and a break away fitting (“BAF”) system that connects the high-pressure side of the pump to the pressurized piping system.
The environment of the wet well also requires that maintenance and replacement of components contained in the wet well be done with minimal exposure of personnel to the liquids and vapors. The submersible pumps used in the wet well will inevitably need to be removed and replaced.
The use of a guide rail system for raising or lowering a submersible pump into the wet well is known in the art and is a conventional solution to this problem, as it accommodates the weight of the pump, which can be considerable.
Accordingly, it would be advantageous to provide a wet well system in which the pump may be installed and removed in a manner that does not present a sparkling hazard in a potentially explosive atmosphere.